1. Field of the Invention
The present invention relates to a musical tone signal generating apparatus, and more particularly to a musical tone signal generating apparatus which generates a musical tone signal corresponding to musical tone waveform data pre-stored in a memory, wherein the musical tone waveform data indicates a musical tone waveform including plural waveforms each having a different cycle.
2. Prior Art
Conventionally, the well-known musical tone signal generating apparatus provides a memory for pre-storing the musical tone waveform data whose read-out operation is controlled by address designation. This apparatus repeatedly reads out the musical tone waveform data in the segment designated by a front address and an end address from such memory to thereby generate the musical tone signal corresponding to the read musical tone waveform data. However, in the case where this conventional apparatus repeatedly reads out the musical tone waveform data within the predetermined segment from the continuous musical tone waveform data indicative of the musical tone waveform which is originally picked up from an external musical instrument, the tone color is not varied smoothly at a time when the conventional apparatus begins to read out the musical tone waveform data at the front portion of segment after reading out the musical tone waveform data at the end portion of segment. For this reason, there must be an unnatural portion to be heard in the generated musical tone.
Therefore, recently, the following musical tone generating apparatus is developed. This apparatus, as disclosed in Japanese Patent Laid-Open Publication No. 59-188697 (i.e., U.S. Pat. No. 4,520,708), makes new musical tone waveform data mainly based on the musical tone waveform data indicative of the original musical tone waveform within the repeatedly reading segment and by use of the weighted addition, whereby this new musical tone waveform data is stored in the memory. More specifically, the musical tone waveform data at the front portion of certain segment is added to musical tone waveform data at the end portion of certain segment as weighted-addition data. Thus, at the time when the apparatus begins to read out the musical tone waveform data at the front portion of segment after reading out the musical tone waveform data at the end portion of segment, there is no unnatural portion to be heard in the generated musical tone. Accordingly, it is possible to obtain the musical tone signal whose tone color is smoothly varied, for example.
However, in the above known apparatus, it is necessary to process the original tone waveform picked up externally before storing the musical tone waveform data in the memory. Therefore, this apparatus is disadvantageous in that such processing is troublesome and the special device for such processing must be required. Especially, it is difficult to process this musical tone waveform data within the musical instrument. Therefore, it is impossible to apply the foregoing musical tone generating apparatus as published in Japan to the musical instrument which picks up the desirable external tone before the performance and immediately thereafter uses the musical tone waveform data concerning such picked-up external tone for the performance. In such case, it is impossible to obtain the musical tone signal whose tone color is varied smoothly so that there will not be unnatural portion to be heard in the generated musical tone, for example.
In addition, the foregoing published apparatus processes the musical tone waveform data at the end portion of segment by use of the musical tone waveform data at the front portion of segment. For this reason, the data at the front and end portions of segment must be fixed. Hence, this apparatus can repeatedly read out the same musical tone waveform data only. Due to such reading process, the tone color of the generated musical tone must be fixed. Accordingly, there is another problem in that it is impossible to obtain the musical tone having the complicated and variable tone colors.